POS0174 PAIN SEVERITY ACROSS HAND OA PHENOTYPES BASED ON A BIOPSYCHOSOCIAL APPROACH
Authors: E. Mulrooney, T. Neogi, H. Solveig Dagfinrud, H. B. Hammer, P. Steen Pettersen, T. K. Kvien, K. Magnusson, I. K. Haugen
Journal: Annals of the Rheumatic Diseases (2022)

Background Hand osteoarthritis (OA) pain is heterogeneous and multifactorial, involving biological, psychological and social aspects extending beyond the OA disease process. Different phenotypes may differ in prognosis and treatments requirements, and thus be of clinical importance. The presence of hand OA phenotypes has not previously been examined. Objectives To explore classes based on a biopsychosocial framework as possible phenotypes in a hand OA population, and examine whether pain severity differ between the classes. Methods Biological, psychological, and social domains were assessed including self-reported questionnaires, clinical assessment and imaging in 300 persons with hand OA. Central pain sensitization was tested by pressure pain thresholds (PPT; kg/cm 2 ) and temporal summation (TS). Variables used for comparison across the classes included age, sex, hand and overall bodily pain severity (Numeric Rating Scales (NRS) last 24h (0-10)). We used Latent Class Analysis followed by posterior fit statistics. Differences in age, sex and pain between classes were assessed by one-way ANOVAs and chi-squared tests. Results We identified 4 classes (Table 1): Class 1 had the lowest hand OA severity, high levels of pain sensitization, comorbidities, sleep problems, psychological distress and the lowest frequencies of working participants. Class 2 had the lowest pain sensitization levels and the highest proportion of participants with university education and living with a partner. Class 3 had the highest level of hand OA severity, and the lowest levels of comorbidity burden and psychological distress. Class 4 was similar to class 1 with high levels of pain sensitization, comorbidities and sleep problems and fewer with university education. Compared with class 1 they had less psychological distress and more severe hand OA. Table 1. Class 1: n=25 (8%) Class 2: n=53 (18%) Class 3: n=103 (34%) Class 4: n=119 (40%) P-value Biological domain OA severity (Kellgren-Lawrence; 0-128 ) 22.2 (15.8) 28.4 (15.6) 33.6 (20.1) 29.7 (20.0) 0.05 PPT tibialis anterior 3.9 (1.8) 9.4 (1.9) 5.6 (1.9) 4.2 (1.6) &lt; 0.001 PPT trapezius 2.8 (0.9) 7.2 (1.8) 4.5 (1.4) 3.4 (1.5) &lt; 0.001 TS change 2.6 (1.7) 0.8 (1.0) 1.4 (1.5) 1.9 (1.6) &lt; 0.001 BMI 28.4 (5.2) 25.7 (4.5) 24.9 (3.6) 27.9 (5.6) &lt; 0.001 Comorbidity burden (0-45 ) 10.7 (4.7) 7.2 (3.5) 4.9 (2.9) 9.8 (3.9) &lt; 0.001 Poor sleep, n (% ) 24 (96%) 30 (57%) 57 (55%) 112 (94%) &lt; 0.001 Psychological domain HADS (0-42 ) 20.9 (5.9) 5.1 (4.4) 4.6 (4.2) 8.0 (4.5) &lt; 0.001 ASES (10-100 ) 47.7 (13.6) 73.8 (9.5) 76.6 (12.7) 63.6 (10.1) &lt; 0.001 PCS (0-52 ) 23.5 (8.3) 9.6 (7.0) 6.3 (5.3) 12.9 (7.1) &lt; 0.001 Social domain University education, n (% ) 13 (52%) 40 (77%) 72 (70%) 48 (41%) 0.01 Working , n (% ) 8 (32%) 38 (72%) 68 (66%) 45 (38%) &lt; 0.001 Living with partner, n (% ) 16 (64%) 34 (71%) 70 (61%) 76 (64%) 0.03 SD=standard deviation; BMI= Body Mass Index; HADS=Hospital Anxiety and Depression Scale; PCS=Pain Catastrophizing Scale; ASES=Arthritis Self Efficacy Scale. Hand and overall pain severity differed significantly between the classes. Class 3 reported the lowest mean (SD) NRS hand and overall pain (2.7 (1.8) and 2.8 (1.7), p=0.01). The highest mean (SD) for NRS hand and overall pain (5.8 (2.7) and 5.8 (2.4), p=0.05) where reported by Class 1, which also had the lowest mean age of 56.9 (SD 6.5), p&lt; 0.001. Class 2 held the highest proportion of men (n=15; 29%), although not significantly different from the other classes. Conclusion Four potential hand OA phenotypes that differed in hand and overall pain severity were identified. The phenotypes with higher levels of pain sensitization, comorbidities, psychological and social burden tended to have more severe hand pain than persons with lower levels. The phenotypes with lowest hand OA severity reported the highest pain severity which may reflect the discordance between OA severity and pain experience. Biopsychosocial factors are likely important in defining hand OA phenotypes and may present a possibility for improved clinical outcomes. Biopsychosocial characteristics across the proposed hand OA phenotypes. Data presented as mean (SD) unless otherwise indicated. Disclosure of Interests Elisabeth Mulrooney: None declared, Tuhina Neogi Consultant of: Regeneron Pfizer/Lilly, Hanne Solveig Dagfinrud: None declared, Hilde Berner Hammer Speakers bureau: Novartis, Lilly, Roche and AbbVie, Pernille Steen Pettersen: None declared, Tore K. Kvien: None declared, Karin Magnusson: None declared, Ida K. Haugen Consultant of: Novartis: Payment to myself, Grant/research support from: Pfizer: Payment to institution